Neil Cockburn, head of the Glasgow office and a specialist in industrial property who had been with the company for 11 years, left abruptly.
News of the departure comes as David Smith, head of the north for rival firm Lambert Smith Hampton, announced he is leaving at the end of the year to set up his own asset management firm. Chicago-headquartered JLLS has not yet said who will replace Cockburn to run the 70-strong operation.
Alasdair Humphery, lead director for Scotland, would not say why Cockburn had left and would not discuss the wider changes in detail, though they are thought to be about cost-cutting. Several more junior staffers are also understood to have departed from across Scotland.
He said: "Our business is 2500 people. There's not anybody that stands still in this world for very long."
It is understood that Cockburn has set up a small consultancy in the short term to handle clients whom he has taken with him, to complete engagements that are already under way. He has signed a six-month non-compete clause with JLLS.
A spokesman for JLLS said: "We have long-established industrial and logistics presence in Scotland and are confident our clients can continue to rely upon the best advice from an experienced team.
"Any further impacts resulting in redundancy from this business review will be minimal and focused on our support functions.
"We will not comment on specific business areas or individuals."